The present invention relates to an improved coupling suited for insulated from ground mounting through an opening in a panel and, more particularly, to an improved coaxial coupling utilizing an integral insulated mounting member and an improved method of manufacturing a coaxial coupling.
In existing coaxial couplings including connectors and adapters suited for mounting on a panel, the outer conductive shell of the coupling commonly serves as a conductive body. Thus, when the outer conductive shell is mounted in a panel of conductive material, the outer conductive shell, being in electrical contact with the panel, is normally shorted to ground (or to whatever other potential the panel may be at). However, there are applications where the shorting to ground of the outer conductive shell cannot be tolerated.
For these applications, various techniques have been developed for insulating the outer conductive shell from the panel. The most common technique presently utilized to insulate a coupling is to insert an insulated bushing between the outer conductive shell or coupling body and the panel. This method also requires that an additional insulating washer be added between the lock washer or nut utilized for securing the coupling to the panel. Another technique which may be utilized to isolate the coupling from the panel, i.e., ground, is to mount an insulating sleeve over the outer conductive shell or coupling body in a fashion whereby the sleeve is the only element which makes contact with the panel, the locking nut, etc., when the coupling is mounted in the panel.
While the techniques indicated above provide an insulated from ground panel or bulkhead coupling, they suffer from a number of substantial shortcomings. First, when an insulated from ground coupling is utilized in place of a standard panel coupling, at least one, and sometimes two, extra parts are required. These additional parts must be handled and assembled on the coupling when the coupling is mounted. Thus, because of these extra parts, the insulated coupling is significantly more expensive to manufacture and utilize than standard panel couplings.
Second, the extra washer, sleeve flanges, or other elements required for insulating the coupling from the panel have a finite thickness which means that, for a given size coupling, the maximum panel thickness which can be accommodated is reduced.
Third, the addition of a bushing or sleeve on the coupling increases the diameter required for the mounting hole. This means that the panel will have to be repunched, or otherwise operated on to increase the hole size in the event that standard size mounting holes have already been punched in the panel, and the increased size required for the holes also reduces the density of couplers which may be accommodated on a given panel. Moreover, the reduction in panel thickness and in the amount of material between mounting openings combine to reduce the strength of the mounting panel.
In summary, it is seen that standard insulated from ground panel couplings are significantly more expensive to manufacture and utilize than standard panel couplings in that (1) they require additional parts; (2) the additional parts must be assembled, increasing the assembly costs; and (3) either standard size mounting openings must be enlarged, possibly requiring the purchase of special tooling to perform this function, or an inventory must be maintained of panels having two different size mounting holes.
From the above, it is apparent that a requirement exists for a panel coupling such as an adapter or a connector having a conductive body or shell which may be easily insulated from ground without resulting in any increase either in the size of the coupling or in the cost of manufacturing and assembling it.